Davewellington at 02:28, 17 December 2021

2021-12-17T02:28:30Z

New page

'''Repairer:''' [http://www.aussiearcade.com.au/member.php/1-Arcade-King Arcade King] 
'''Forum Thread:''' [http://www.aussiearcade.com.au/showthread.php/23513-Black-Dragon-Repair Black Dragon PCB Repair] 
 
Brad's Original Black Dragon (Tiger) PCB

PCB was missing 2 roms a 27512 @ 9B and 27256 @ 2N

The rom at 2N is for all the in game foreground text and 9B is part of the background.

First things first replaced the 2 missing roms.

'''Problem:''' Foreground text is all messed up. 
 
 
[[File:Pcb repair black dragon 1.jpg]]
 
 
'''Fix:''' Pin 23 (A11) on rom 2N was stuck High. Tracked back to pin 2 of a 74ls253 @ 3N. Replacing the chip fixed the problem. 

'''Problem:''' Character Graphics have faint horizontal lines through them. 
 
 
[[File:Pcb repair black dragon 2.jpg]]
 
 
'''Fix:''' Faulty 74ls253 @ 2K. Both chips were TI (Texas Instruments) branded IC's 
 
[[File:Pcb repair black dragon 3.jpg]]
 
 

Board now 100%

'''Repair Logs converted to wiki format by Brad from [http://www.aussiearcade.com.au Aussie Arcade]'''.

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'''Repairer:''' Apocalypse 
'''Source:''' [https://web.archive.org/web/20191230200208/http://arcadefixer.blogspot.com/2017/06/ Black Dragon - Capcom 1987 (repair log)] 
Great story about this game. I got it in a local auction for $1 (the minimum bid) thanks to my friend Kelvin who sent me the link. 

I placed only one bid and then forgot about the auction. I had set a reminder in my phone but mistankenly entered the wrong time. So I got the reminder 40 minutes after the end of the auction. When I switched off the alarm I saw I had an email on my phone. It was the auction site confirming I won the auction! Nobody else bidded. Probably cause the board was advertised as faulty and there are very few arcade repairers over there in New-Zealand. 

When I received the board I promptly noticed the game has been repaired before as the work RAM had been put on a socket. For once it was a clean job so this didn't bugger me. Otherwise it was in very good nick.
I powered it and was really surprised to see the game was almost 100% perfectly running (and discovered it was the Japanese version of the game "Black Dragon" despite the seller advertising it as "Black Tiger"). Only fault I could find was when the sprites were close to either the left or the right border they were repeated on the other side with jailbars on them. 
[[File:ApocBD_1.JPG]] 

As always I identified the function of each RAM, piggybacked them and probed few IC with no clear culprit. To me it was a counter issue (I found a LS163 next to the sprites RAMs) but before spending more time on the board I contacted Caius from JAMMARCADE who confirmed what I thought: probable counter issue. 

I went back to the repair and probed all the LS163 of the video board. One of them had pin 10 not connected to anything. This surely wasn't normal as it's the CET input. I couldn't figure out where it should be connected. So I pulled the chip to see the traces underneath. After doing so I was left with only one possibility: trace going to pin 7 was the only possible trace that could be connected to pin 10. I compared with others LS163 on the board and surely pins 7 and 10 were bridged. I installed a socket, put back the chip in it and ran a wire between pins 7 and 10. Problem vanished. 
[[File:ApocBD_2.JPG]] 

I then spent the rest of my afternoon playing the game as it's one of my favorites. 

Game fixed. 

[[Category:Repair Logs]]

Black Dragon Repair Logs - Revision history

Davewellington at 02:28, 17 December 2021